long term memory - final Flashcards
priming
change in stimulus processing due to prior exposure to same/similar sim w/o conscious awareness
- depends on region of cortex processing relevant representations
perceptual priming
- warrington and wieskrantz
- korsakoffs syndrome patients
- amnesia due to severe alcoholism
- participants improved day to day, w/o remembering precious days training
- sensory cortices
semantic priming
rossel, price & Nobre
- task : lexical decision-word or non word
- unimodal & multimodal association cortices (anterior temporal, inferior parietal, prefrontal cortex)
semantic memory (facts)
- world, object, and language knowledge, conceptual priming
- medial temporal lobe, middle diencephalon & neocortex
semantic memory (parts of the brain)
memory for concrete word meanings activate areas of cortex involved in relevant processing
- actions: motor cortex/somatosensory cortex
- sounds: auditory cortex
- colours & movements: ventral visual stream (occipital/temporal cortex)
sensory/functional theory
- organization of semantic representations based on relevant sensory and motor features
- eg. action words activate primary motor cortex
( lick-face, pick-arm, kick-leg)
domain-specific theory
organization of semantic representation based on semantic categories
- fruit & veg: lettuce, apple
- animate living things: dog, cat, snake
- conspecifics: mom, dad, mailman
sensory/functional VS domain-specific
- tools associated with actions (premotor cortex activation)
- animals associated with appearance ( posterior temporal cortex, ventral stream)
abstract semantic knowledge
- involves multiple modalities
- “sports”: images, sounds, actions, etc
- distributed representations
- -> integrating hub in anterior temporal lobe
semantic memory formation
- starts as episodic memory
- knowing a fact but not knowing where you learned it first ( eg. sky is blue)
episodic memory (events)
- specific personal experiences from a particular time and place
- medial temporal lobe, middle diencephalon & neocortex
encoding episodic memory
- PFC, PPC, HC form indices to bind ot cortical receptors
- memory of halloween party (saw sam dressed as elmo, smoky music, ate M&Ms)
- cortex represents Sam, Elmo, spooky music etc
- hippocampus binds together
retrieval of episodic memory
- PFC, PPC, HC, uses indices to reinstantiate cortical representations
- e.g. memory of halloween, when sam dressed as elmo
- sam & elmo act as retrieval cues
- activates indices in HC
- activate representation of event in cortex
role of PFC in episodic encoding & retrieval
important in executive control of memory processes, goal maintenance and top-down attention
role of PPC in episodic encoding & retrieval
important for attention control during memory processes, including top-down and bottom-up attention
cognitive map theory
- memory for spatial relationships in environment
- place cells, fire when animal is in specific location
relational memory theory
- memory for associations in general
- odor association task: trained to prefer some scent over others, lesion to fornix
subregions of the temporal lobe (3)
perirhinal cortex, parahippocampal cortex, hippocampus
perirhinal cortex
binding features of objects
oarahippocampal cortex
encoding spatial layout
hippocampus
encoding relationships more generally
long term potentiation
increase in synaptic strength, in hippocampus
- early LTP: increase presynaptic release of NTS and # of postsynaptic receptors
- late LTP: increase # of dendritic spines and synapses
long term depression
- when presynynaptic AP doesnt lead to post-synaptic AP, connection weakened
- decrease of NT released, # of receptors and synapses
episodic retrieval: reconstruction
best guess based on :
memory trace, genes, past experience, internal state, environmental context
inaccuracy of episodic retrieval due to (5)
- semantic relatedness
- cultural experience
- source misattributions
- pragmatic inferences
- misleading post event information
false memory task
presented list of semantically related words (bed, tired, rest, awake, dream)
- recall/recognition test: words on list (tired, rest), unrelated distractors (cake, mountain), semantically related cues (sleep)
deese, roediger, and mcdermott (false memory)
- related lies reported almost as often as actual words on list
- high confidence in accuracy
- often report seeing the lure word
amnesia
- removal of bilateral rem portal lobes in patient
- severe anterograde amnesia (no new memory after surgery)
- temporally graded retrograde amnesia (unable to recall LTMs from right before surgery)
why 2 memory systems?
hippocampus-
- learns rapidly, created distinct memories for each event, more important for episodic memories
cortex
- learns slowly, extracts generalities across events, more important for semantic memories
